The goal of this K-23 award is to provide the applicant, a psychiatrist with advanced training in both child/adolescent and addiction psychiatry, with the advanced training needed to develop a paradigm to study and treat the transmission of addictive vulnerability (AV) among high-risk families. Preceptors and consultants for this award have been selected with the long-range intent of designing interventions to reduce AV through the treatment of parental addiction, child externalizing behavior (CXB), and the improved identification of communication problems within these families. Formal education in therapeutic interventions (including behavioral, psychoeducational and psychopharmacological approaches) and statistical methods complement this training. Among families with addicted parents, CXB may mediate the transmission of AV. Hence early identification and effective treatment of CXB may also reduce AV. Although parental substance abuse has multiple deleterious effects on children, little is known regarding the needs of these children and their families once their parents are treated for addiction. CXB is closely linked to coercive patterns of interaction between parents and their children, and these interactions may adversely effect both children and parents. A one-year prospective study of 100 families with a parent-proband in methadone maintenance treatment and their 6-9 year old children has been designed to better identify the treatment needs of these families. Parental substance use will be prospectively assessed as a predictor of child externalizing behavior, considering parent-child interactions as mediators or moderators of this relationship. The role of additional parent (e.g., comorbid psychopathology, gender, exposure, ethnicity, SES) and child (baseline externalizing behavior, comobid psychopathology, language ability) factors will also be considered in this developmental model of addictive vulnerability.